1. Field of the Invention
The present invention relates to a method for the recovery of nucleic acids from a nucleic acid-containing substance. In more detail, it relates to a method for the recovery of nucleic acids, which is suitable for an automatic device for the recovery of nucleic acid components as endogenous or exogenous genes from humor components for gene diagnosis by means of nucleic acid assays, or suitable for an automatic device for the recovery of plasmid DNAs from recombinant E. coli or the like for base sequencing of nucleic acids.
2. Description of the Related Art
A multitude of genetic technologies have been developed based upon advances in molecular biology, and a number of morbid genes have been isolated and identified according to these technologies. As a result, molecular biological techniques have been adopted as techniques for diagnosis or examination in the field of medical care so as to enable diagnosis which have been unable to conduct or to shorten the period of examination remarkably.
The significant advances largely owe to gene amplification techniques, and particular to polymerase chain reaction (hereinafter referred to as PCR: Saiki et al., Science, 239,487-491(1988)) techniques.
The PCR technique enables nucleic acids in a solution to amplify sequence-specifically so that it provides, for example, an indirect proof of the presence of a trace quantity of a virus in serum by amplifying and detecting nucleic acids as the viral gene.
The PCR technique is, however, somewhat disadvantageous in the use for clinical daily examinations. In particular, there are some difficulties in extraction and purification steps of nucleic acids in a pretreatment according to this technique, whereas the extraction and purification steps of nucleic acids have been indicated to be key steps (Ooshima et al., JJCLA 22(2),145-150(1997)).
These difficulties are attributed to inhibitory factors remaining in the purification step of nucleic acids, and known inhibitory factors include hemoglobin in blood, surfactant used in the extraction step and the like.
In addition, the extraction step requires a complicated procedure and a large amount of skilled labor. Therefore, this step is an obstacle to a new introduction of the genetic test into laboratories of hospitals, and the automatization of this step has been demanded.
On the contrary, plasmid DNAs are frequently used as materials for genetic engineering, and automatization of the extraction and purification steps of nucleic acids has been demanded from the viewpoint of labor savings in institutions for molecular biological research, as well as in the laboratories.